JP6953937B2 - Conveyor device and image forming device - Google Patents

Description

The present invention relates to a transport device and an image forming device.

Patent Document 1 below discloses an image forming apparatus provided with a movable curl correction mechanism that corrects curl of paper during backside printing. In this image forming apparatus, the paper is made to collide with the paper guide, the curl is corrected so that the entire axial direction of the paper is lifted, and then the paper guide is opened to convey the paper.

Patent Document 2 below discloses an image forming apparatus provided with a movable curl correction mechanism that corrects curl of paper during backside printing. In this image forming apparatus, curl is corrected so that the entire axial direction of the paper is lifted by passing the paper through a transport path that projects downward with respect to the return path formed by the guide member and the rubber roller.

Japanese Unexamined Patent Publication No. 2003-165663 Japanese Unexamined Patent Publication No. 2000-219387

In the present invention, the top of the pressing member in the central portion in the width direction is separated from the top of the protruding member at the end in the width direction in the thickness direction of the recording medium when viewed from the transport direction of the recording medium. It is an object of the present invention to obtain a transport device that suppresses curling at the time of image formation on the second surface of the medium and reduces wrinkles of the recording medium.

The transfer device according to the first aspect is provided in an inversion path in which the recording medium is conveyed to the image forming section and then the front and back of the recording medium are inverted and conveyed to the image forming section, and the inversion path is provided for the recording. A pair of transport rolls for transporting a medium and a pair of transport rolls provided at the widthwise end of the reversal path, projecting from the side of one transport roll to the side of the other transport roll beyond the nip of the pair of transport rolls. The recording is provided from the direction opposite to the pushing direction of the recording medium by the protruding member, which is provided on the central side with respect to the protruding member that pushes the end portion in the width direction of the recording medium and the protruding member in the width direction of the reversal path. It has a pressing member that hits the medium and is arranged so that the top thereof overlaps the top of the protruding member when viewed from the transport direction of the recording medium.

The transport device according to the second aspect is the transport device according to the first aspect , wherein the image forming unit is an image of the recording medium on which an image is formed when the recording medium is conveyed along the inversion path. The central portion in the width direction of the surface is curled so as to project from the end portion in the width direction toward the pressing member, and the protruding member is formed from the anti-image surface on which the image of the recording medium is not formed. Upon hitting the recording medium, the pressing member hits the recording medium from the image surface of the recording medium.

The transport device according to the third aspect is the transport device according to the first or second aspect , in which the protruding member is arranged outside the short side of the A4 size recording medium in the axial direction.

The transport device according to the fourth aspect is the transport device according to the third aspect , in which the pressing member is arranged outside the short side of the A4 size recording medium in the axial direction.

The conveying device according to the fifth embodiment, the conveying device according to any one aspect of the first aspect to the fourth aspect, wherein the projecting member and the pressing member, at least in the conveying direction of the recording medium Part of it is arranged so that it overlaps.

Conveying device according to a sixth aspect, in the conveying device according to any one aspect of the first aspect to the fifth aspect, wherein the protruding member is a projection projecting from the guide of the reversing path.

The transport device according to the seventh aspect is the transport device according to the sixth aspect , in which the top of the protrusion is curved in an R shape and is along the portion on the upstream side of the top of the protrusion and the transport direction of the recording medium. The angle with the vertical line is smaller than the angle between the portion downstream of the top of the protrusion and the line along the transport direction of the recording medium.

Conveying device according to an eighth aspect, in the conveying device according to any one aspect of the first aspect to the seventh aspect, wherein the pressing member is a projection projecting from the other guide of the reversing path ..

Conveying device according to the ninth aspect, in the conveying device according to any one aspect of the first aspect to the seventh aspect, wherein the pressing member, wherein the two transport rollers for conveying the recording medium It is composed of a transport roll provided on the opposite side of the projecting member.

The image forming apparatus according to a tenth aspect, the toner image forming unit for forming a toner image on the surface of the recording medium, and a fixing unit for fixing by heating and pressurizing the toner image on the surface of the recording medium, the fixing than section having a conveying device according to any one aspect from the first embodiment is disposed at the conveying direction downstream side of the recording medium to the ninth aspect.

According to the transport device according to the first aspect , the top of the pressing member at the center in the width direction is separated from the top of the protruding member at the end in the width direction in the thickness direction of the recording medium when viewed from the transport direction of the recording medium. Compared with the above configuration, curling during image formation on the second surface of the recording medium is suppressed, and wrinkles of the recording medium are reduced.

According to the transport apparatus according to the second embodiment, the protruding member in comparison with a structure that is shaded from the recording medium from the inverted image plane, curling at the time of image formation on the second surface of the recording medium is suppressed, the recording medium Wrinkles are reduced.

According to the transport device according to the third aspect , the paper transport that is fed from the short side of the A4 size is compared with the configuration in which the projecting member is arranged only axially inside the short side of the A4 size recording medium. Does not interfere.

According to the transport device according to the fourth aspect , the paper transporter fed from the A4 short side is compared with the configuration in which the pressing member is arranged only axially inside the short side of the A4 size recording medium. Does not interfere.

According to the transport device according to the fifth aspect , when the image is formed on the second surface of the recording medium, as compared with the case where the projecting member and the pressing member are arranged apart from each other in the transport direction of the recording medium. Curling is suppressed and wrinkles on the recording medium are reduced.

According to the transfer device according to the sixth aspect , the structure is simple as compared with the configuration in which the projecting member does not project from the guide.

According to the transport device according to the seventh aspect , poor transport of the recording medium is suppressed as compared with the member having an isosceles triangle shape of the protrusion.

According to the transport device according to the eighth aspect , the structure is simple as compared with the configuration in which the pressing member does not protrude from the guide.

According to the transfer device according to the ninth aspect , the structure is simple as compared with a configuration in which the pressing member is not a transfer roll of one of the two transfer rolls.

According to the image forming apparatus according to the tenth aspect , the top of the pressing member at the center in the width direction is separated from the top of the protruding member at the end in the width direction in the thickness direction of the recording medium when viewed from the transport direction of the recording medium. When the recording medium is curled at the fixing portion, the curl at the time of forming an image on the second surface of the recording medium is suppressed, and the wrinkles of the recording medium are reduced.

It is a block diagram which shows the image forming apparatus provided with the transfer apparatus which concerns on 1st Embodiment. It is a block diagram which shows the vicinity of the reversal path in the transport device which concerns on 1st Embodiment. It is a side view which shows the transport device which concerns on 1st Embodiment. It is a top view which shows the transport device which concerns on 1st Embodiment. (A) is a schematic side view which shows the curl state of the paper which is conveyed in the reversal path in the transfer apparatus which concerns on 1st Embodiment, and (A) is a schematic side view which shows the state of curl of the paper which is conveyed in the reversal path, and (A) is the transport device which concerns on 1st Embodiment. , Is a schematic plan view showing a direction for correcting curl of paper. It is a top view which shows the transport device which concerns on 2nd Embodiment. It is a side view which shows the transport device which concerns on 3rd Embodiment. It is a side view which shows the transport device which concerns on 4th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The direction indicated by the arrow H appropriately shown in the drawing is the device height direction (vertical direction), and the direction indicated by the arrow W is the device width direction (horizontal direction). Further, the direction indicated by the arrow D, that is, the direction orthogonal to each of the device height direction and the device width direction is defined as the device depth direction (horizontal direction).

[First Embodiment]
An example of the image forming apparatus provided with the conveying apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 5. In the following, yellow is represented by Y, magenta is represented by M, cyan is represented by C, and black is represented by K, and when it is necessary to distinguish each component and toner image (image) by color, the reference numerals are used. A color code (Y, M, C, K) corresponding to each color will be added to the end for description. Further, in the following, when each component and the toner image are generically referred to without being distinguished for each color, the code of the color at the end of the code will be omitted.

(Overall configuration of image forming apparatus)
FIG. 1 shows an example of the configuration of the image forming apparatus according to the present embodiment. As shown in FIG. 1, the image forming apparatus 10 includes an image reading unit 90 and an apparatus main body portion 92. The image reading unit 90 includes a document conveying unit 94 and a document reading unit 96, and the document conveying unit 94 can be opened and closed above the document reading unit 96 centering on the connecting unit 98.

The apparatus main body 92 includes a paper accommodating unit 12 for accommodating paper P as an example of a recording medium, a toner image forming unit 14, a transport unit 16, a fixing unit 18, a discharge unit 20, a replenishment mechanism 22, and a control unit 24. It is configured. The toner image forming unit 14 includes four image forming units 40Y, 40M, 40C, 40K, and a transfer unit 50. Here, yellow (Y), magenta (M), cyan (C), and black (K) are examples of toner colors. Each of the image forming units 40Y, 40M, 40C, and 40K includes a photoconductor 42, a charging device 44, an exposure device 30, a developing device 46, and a cleaning device 48. In each image forming unit 40Y, 40M, 40C, 40K, a toner image of each color of yellow (Y), magenta (M), cyan (C), and black (K) is formed on the outer peripheral surface of each photoconductor 42. Further, the image forming units 40Y, 40M, 40C, and 40K are arranged in a state of being inclined and arranged in a direction intersecting with the device width direction. Here, the toner image forming portion 14 and the fixing portion 18 are examples of the image forming portion.

The photoconductor 42 has a function of holding a toner image developed by the developer 46. The photoconductor 42 is formed in a cylindrical shape, has a photosensitive layer on its surface, and is rotationally driven in the direction of an arrow by a driving means (not shown).

The developer 46 develops the latent image formed on the photoconductor 42 as a toner image. The developing device 46 includes a developing roll 80 that supplies toner to the outer peripheral surface of the photoconductor 42, and two transporting members 82 and 84 that transport the developer containing toner and carriers to the developing roll 80. The replenishment mechanism 22Y, 22M, 22C, 22K replenishes the developer to the developer 46 of each color.

The transfer unit 50 includes a transfer belt 52, a primary transfer roll 54 of each color, a drive roll 56, and a secondary transfer roll 58. The posture of the transfer belt 52 is determined by four primary transfer rolls 54, a support roll 55, a drive roll 56, and a tension applying roll 59 that come into contact with the inner peripheral surface thereof. The transfer belt 52 is provided with a cleaning device 70 on the downstream side of the secondary transfer position T1. The outer peripheral surface of each photoconductor 42 constituting each image forming unit 40 is in contact with the lower outer peripheral surface of the transfer belt 52.

The transport unit 16 includes a delivery roll 16A, a plurality of transport roll pairs 16B and 17B, and a discharge roll 16E, and transports the paper P fed by the delivery roll 16A to the discharge unit 20. Further, the transport unit 16 is provided with a transport device 100 provided with an inversion path 102 that reverses the front and back of the paper P and transports the paper P to the toner image forming unit 14 without discharging the paper P to the discharge unit 20. .. The plurality of transfer roll pairs 16B and 17B are arranged along the transfer path 16C in which the paper P is conveyed, and the secondary transfer position T1 which is a position where the paper P is opposed to the drive roll 56 and the secondary transfer roll 58. Transport to. The transport roll pair 17B is configured as a pair of alignment rolls that match the transport timing of the paper P. In the present embodiment, for example, the secondary transfer roll 58 is grounded, the drive roll 56 forms the counter electrode of the secondary transfer roll 58, and the drive roll 56 is applied with the secondary transfer voltage. As a result, the toner image is transferred to the paper P. The transport device 100 will be described later.

Further, the fixing portion 18 is provided on the downstream side of the secondary transfer position T1 in the transport direction of the paper P. The fixing portion 18 includes a heating rotating body 18A that heats a toner image on the surface of the paper P, and a pressurized rotating body 18B that presses the paper P against the heating rotating body 18A from the back side, and is secondarily transferred to the paper P. The toner image is fixed on the paper P.

(Action of image forming device)
In the image forming apparatus 10, an image is formed as follows.

In the image forming apparatus 10, the exposure light emitted from the exposure apparatus 30 by the apparatus main body 92 according to the image data of each color is incident on the outer peripheral surface of the photoconductor 42 charged by the charging apparatus 44, and each photoconductor. A latent image corresponding to the image data of each color is formed on the outer peripheral surface of the 42. The latent image formed on the outer peripheral surface of each photoconductor 42 is developed as a toner image of each color by each developer 46. The toner images of each color on the outer peripheral surface of each photoconductor 42 are primarily transferred to the outer peripheral surface of the transfer belt 52 by the primary transfer rolls 54 facing each other.

Further, the paper P is sent out from the paper accommodating portion 12 and conveyed to the secondary transfer position T1 at the timing when the toner images of each color primary transferred to the transfer belt 52 reach the secondary transfer position T1. At the secondary transfer position T1, the toner images of each color on the transfer belt 52 are secondary transferred to the surface of the paper P. Further, the paper P on which the toner image is transferred is conveyed toward the fixing portion 18, heated and pressurized by the heating rotating body 18A and the pressurized rotating body 18B, and after the toner image is fixed on the paper P, the toner image is fixed. The paper P is ejected to the ejection unit 20.

On the other hand, when forming an image on both sides of the paper P, the paper P is conveyed to the reversing path 102 by rotating the discharge roll 16E in the reverse direction with the rear end portion of the paper P sandwiched. Then, the rotation of the transfer roll pair 17B transfers the paper P to the secondary transfer position T1 at a predetermined timing, and the toner image is transferred from the transfer belt 52 to the back surface of the paper P as the second surface (FIG. 2). reference). Further, the toner image transferred to the back surface of the paper P is fixed to the paper P by the fixing portion 18. Then, the paper P on which the toner image is fixed is discharged to the discharge unit 20 by the rotation of the discharge roll 16E.

In the image forming apparatus 10, there is only one paper accommodating unit 12, but instead of this configuration, a plurality of paper accommodating units 12 for accommodating a plurality of sheets P having different sizes are provided, and a plurality of paper accommodating units are provided. Paper P may be conveyed from 12 along the transfer path 16C by the transfer unit 16.

(Structure of transport device 100)
Next, the transport device 100, which is a main part of the image forming device 10 of the present embodiment, will be described.

<Reversal path 102>
As shown in FIG. 2, the transport device 100 includes an inversion path 102 arranged on the side of the toner image forming unit 14 (see FIG. 1), that is, on the secondary transfer roll 58 side with respect to the transfer unit 50. Further, the transport device 100 includes a pair of transport rolls 104 and 106 that are arranged along the reversing path 102 and that transport the paper P. In the inversion path 102, as described above, the paper P having the toner image fixed on the surface as the first surface of the paper P is not discharged as it is to the discharge unit 20 (see FIG. 1) by the discharge roll 16E, and the paper is not discharged as it is. It has a function of inverting the front and back of the paper P in order to form a toner image on the back surface of the P as the second surface. In the reversing path 102, the paper P is transported so as to reverse the front and back of the paper P from the discharge roll 16E toward the transport roll pair 17B. As an example, the transport device 100 has a plurality of guides 126 arranged along the outside of the reversing path 102.

<A pair of transport rolls 106>
As shown in FIGS. 2 and 3, a pair of transport rolls 106 are arranged at a portion of the reverse path 102 where the paper P is linearly transported. The transport roll 106 includes a roll 106A as an example of one transport roll arranged on the side (opposite side of the transfer unit 50) of the anti-image surface 4 (see FIG. 4) on which the image of the paper P is not formed, and the paper. A roll 106B as an example of the other transport roll arranged on the side (the side of the transfer unit 50) of the image surface 2 (see FIG. 4) on which the image of P is formed is provided. Then, the nip N is formed by the contact between the roll 106A and the roll 106B. The roll 106A includes a rotating shaft 122, and the rotating shaft 122 is rotatably supported by a housing (not shown). Further, the roll 106B includes a rotating shaft 124, and the rotating shaft 124 is rotatably supported by a housing (not shown). As an example, by driving one of the roll 106A and the roll 106B, the other of the roll 106A and the roll 106B is driven to rotate.

In the portion of the reversing path 102 where the paper P is conveyed in a straight line, the paper P is on the reversing path 102 with the image surface 2 (see FIG. 4) of the paper P facing the transfer unit 50 (see FIG. 2). It is conveyed in the vertical direction (arrow A direction) from the upper side to the lower side. A plurality of pairs of transport rolls 106 (two sets in this embodiment) are arranged in the device depth direction (arrow D direction), that is, in the width direction of the paper P (see FIG. 4). In the reversing path 102, the paper P is sandwiched between the nip N of the roll 106A and the roll 106B and conveyed. In the present embodiment, the outer diameter of the roll 106A is smaller than the outer diameter of the roll 106B, but the present invention is not limited to this configuration and can be changed.

As shown in FIGS. 2 to 4, the transport device 100 is composed of a projecting member 110 that pushes the widthwise end of the sheet P from the side of the anti-image surface 4 (see FIG. 4) of the sheet P, and the projecting member 110. A pressing member 114 that hits the paper P from a direction opposite to the pushing direction of the paper P is provided. The projecting member 110 and the pressing member 114 are arranged on the downstream side in the transport direction with respect to the pair of transport rolls 106.

<Protruding member 110>
The projecting member 110 is provided at the end of the reversing path 102 in the width direction (see FIG. 4). That is, the projecting members 110 are arranged at both ends in the device depth direction (arrow D direction). Here, the "edge in the width direction of the reversing path 102" is preferably in the range of 30% from the edge in the width direction of the maximum size paper P conveyed on the reversing path 102, and the maximum size paper P. More preferably, it is in the range of 20% from the edge in the width direction. The projecting member 110 is provided so as to project from a guide 112 arranged on one side (opposite side to the transfer unit 50) along the reversing path 102. The guide 112 defines the inversion path 102. The projecting member 110 projects from the roll 106A side to the roll 106B side beyond the nip N of the pair of transport rolls 106 (see FIG. 3). In the present embodiment, the projecting member 110 is configured as a protrusion that projects from the guide 112 arranged along the reversing path 102 so as to cross the transport locus of the paper P (the transport locus of the paper P by the pair of transport rolls 106). ing.

As shown in FIG. 3, the projecting member 110 is formed in a triangular shape with the guide 122 as the base when viewed from the device depth direction (D direction). That is, the projecting member 110 projects most on the upstream side inclined portion 110A that inclines to the side that protrudes on one side (arrow W direction) in the device width direction with respect to the surface of the guide 112, and on the downstream side of the upstream side inclined portion 110A. It includes a top portion 110B and a downstream side inclined portion 110C that inclines from the top portion 110B toward the surface of the guide 112. Here, the upstream inclined portion 110A is an example of an upstream portion, and the downstream inclined portion 110C is an example of a downstream portion. In the triangular protruding member 110, the angle α (angle of the triangular corner) between the surface of the guide 112 and the upstream inclined portion 110A is the angle β (triangular) between the surface of the guide 112 and the downstream inclined portion 110C. The angle of the corner) is smaller than. In other words, the angle between the upstream portion of the top 110B of the protruding member 110 and the line along the transport direction of the paper P is the line along the downstream portion of the top 110B of the protruding member 110 and the transport direction of the paper P. It is smaller than the angle with. Further, the top portion 110B has an R-shaped curved shape when viewed from the device depth direction (D direction).

As shown in FIG. 4, the projecting member 110 is axially outside the short side 6 of the A4 size paper P (A4) when the A4 size paper P (A4) is conveyed to the reversing path 102. Is located in. Here, the transport device 100 is a system in which the central portion of the paper P in the width direction is aligned with the central portion of the reversing path 102 in the width direction (device depth direction). In FIG. 4, the paper P (A4) is schematically displayed as a reference example so that it can be compared with the position of the protruding member 110.

<Pressing member 114>
As shown in FIGS. 2 to 4, the pressing member 114 is provided on the central side with respect to the projecting member 100 in the width direction of the reversing path 102 (see FIG. 4). The pressing member 114 is provided so as to project from the guide 116 arranged on the other side (the side of the transfer unit 50) along the reversal path 102. The guide 116 defines the inversion path 102. The pressing member 114 projects to the opposite side of the protruding member 110. In the present embodiment, the pressing member 114 is configured as a protrusion protruding from the guide 116 of the reversing path 102 toward the transport locus side of the paper P. Here, the guide 116 is an example of another guide.

As shown in FIG. 3, the pressing member 114 is formed in a triangular shape when viewed in the device depth direction (D direction). That is, the pressing member 114 protrudes most on the upstream side inclined portion 114A that inclines to the side that protrudes on the other side (arrow W direction) in the device width direction with respect to the surface of the guide 116, and on the downstream side of the upstream side inclined portion 114A. It is provided with a top portion 114B to be formed and a downstream side inclined portion 114C that is inclined from the top portion 114B toward the surface of the guide 116.

The projecting member 110 and the pressing member 114 are arranged so that at least a part of the projecting member 110 and the pressing member 114 overlap each other in the conveying direction of the paper P. In other words, a part of the projecting member 110 and a part of the pressing member 114 overlap with each other along the conveying direction of the paper P. In the present embodiment, the projecting member 110 and the pressing member 114 overlap each other in the region C in FIG. 3 in the transport direction of the paper P.

Further, the top 114B of the pressing member 114 is arranged so as to overlap the top 110B of the protruding member 110 when viewed from the transport direction of the paper P. That is, when viewed from the transport direction of the paper P, the top 114B of the pressing member 114 and the top 110B of the protruding member 110 overlap each other in the region B in FIG. In the present embodiment, as an example, the top 114B of the pressing member 114 is arranged on an extension line of the nip N of the pair of transport rolls 106 when viewed from the transport direction of the paper P. Instead of this configuration, the top 114B of the pressing member 114 may be arranged at a position not exceeding the extension line of the nip N of the pair of transport rolls 106 when viewed from the transport direction of the paper P.

In the present embodiment, the top 114B of the pressing member 114 is arranged on the downstream side of the top 110B of the protruding member 110 in the transport direction of the paper P when viewed from the depth direction of the device (arrow D direction). The distance between the top 114B of the pressing member 114 and the top 110B of the protruding member 110 in the transport direction of the paper P is, for example, preferably 0 to 10 mm, more preferably 0 to 7 mm, and even more preferably 0 to 5 mm.

As shown in FIG. 4, two pressing members 114 are arranged in the device depth direction (arrow D direction), and are closer to the center than the projecting members 110 at both ends in the device depth direction (arrow D direction). Is located in. The distance (interval) between the pressing member 114 and the projecting member 110 is, for example, preferably 0 to 120 mm, more preferably 5 to 15 mm, and even more preferably 7 to 10 mm.

Further, as an example, the pressing member 114 is arranged outside the short side 6 of the A4 size paper P (A4) in the axial direction when the A4 size paper P (A4) is conveyed to the reversing path 102. Has been done.

The fixing portion 18 of the image forming apparatus 10 is, for example, as shown in FIGS. 5A and 5B, when the paper P is conveyed along the inversion path 102 after fixing the toner image on the surface of the paper P. The central portion P1 of the image surface 2 of the paper P in the width direction is easily curled so as to protrude toward the pressing member 114 (see FIG. 4) from the end portion P2 of the paper P in the width direction. In other words, in the vicinity of the pair of transport rolls 106 of the reversing path 102, the central portion P1 in the width direction of the image surface 2 of the paper P is curled so as to protrude toward the transfer unit 50 from the end portion P2 in the width direction of the paper P. Cheap. That is, it is easy to curl so that the image surface 2 of the paper P is convex and the anti-image surface 4 of the paper P is concave. In the image forming apparatus 10, the projecting member 110 hits the paper P from the anti-image surface 4 of the paper P to push the paper P in the direction of the arrow B opposite to the curl direction of the paper P (FIG. 10). 5 (B)). Further, the pressing member 114 hits the paper P from the image surface 2 of the paper P to press the paper P from the direction of the arrow C on the curl side of the paper P (see FIG. 5B).

(Action and effect)
Next, the operation and effect of this embodiment will be described.

In the image forming apparatus 10, when forming an image on both sides of the paper P, the paper P passes through the fixing portion 18 and the toner image on the surface of the paper P is fixed, and then the paper P is switched by the ejection roll 16E. It is backed up and conveyed on the reversal path 102. For example, in the image forming apparatus 10, as shown in FIGS. 5A and 5B, when the paper P is conveyed along the reversal path 102 after fixing, the central portion of the image surface 2 of the paper P in the width direction. It is easy to curl so that P1 projects toward the pressing member 114 (see FIG. 4) from the widthwise end P2 of the paper P.

In the image forming apparatus 10, the paper P conveyed on the reversing path 102 passes through the position where the projecting member 110 and the pressing member 114 are arranged on the downstream side of the pair of conveying rolls 106. At this time, the projecting member 110 hits the end portion P2 in the width direction of the paper P from the anti-image surface 4, and the pressing member 114 hits the central portion P1 in the width direction of the paper P from the image surface 2. As a result, the anti-image surface 4 of the widthwise end P2 of the paper P hits the projecting member 110 and is pushed in the arrow B direction opposite to the curl direction of the widthwise end P2 of the paper P (). (See FIG. 5B). Further, the image surface 2 of the central portion P1 in the width direction of the paper P hits the pressing member 114 on the inner side in the width direction of the protruding member 110, so that the central portion P1 in the width direction of the paper P is in the direction of the arrow C on the curl side. Paper P is pressed from (see FIG. 5B). As a result, the curl of the paper P is corrected.

After that, the paper P is conveyed to the secondary transfer position T1 by the pair of transfer rolls 104 and the transfer rolls 17B, and the toner image is transferred to the back surface of the sheet P. Further, the paper P is conveyed to the fixing portion 18, and the toner image on the back surface of the paper P is fixed by heating and pressurizing. At this time, since the curl of the paper P is corrected by the transport device 100, the paper P is transported to the fixing portion 18 in a state where the disorder of the transport posture of the paper P is suppressed.

Generally, in an image forming apparatus, paper P is conveyed by forming a nip with two opposing rolls and rotating the two rolls while applying a constant pressure. When the paper P passes through the nip of the two rolls, a force for bending the paper P is applied, and the paper P may be curled. The axial arrangement of the roll, the pressure of the nip, etc. are various, and the curl formation and size at each location are different. In particular, in the fixing portion where the pressure of the nip is strong and the paper P is conveyed while applying heat, the paper P is likely to be curled. When the paper P is curled, the transport posture of the paper P changes. For example, when the toner image on the surface of the paper P is fixed, if a curl occurs so that the end portion of the paper P in the width direction with respect to the transport direction of the paper P rises to the side opposite to the heating rotating body, the transport posture of the paper P Is easily disturbed, and wrinkles are likely to occur on the paper P when the toner image on the back surface of the paper P is fixed. In the fixing portion 18, wrinkles are likely to occur on the paper P because the positions of the tips of the paper P are different between the front side and the back side of the paper P in the device depth direction (arrow D direction).

In the transport device 100 of the present embodiment, the anti-image surface 4 of the widthwise end P2 of the paper P hits the projecting member 110, so that the arrow is in the direction opposite to the curl direction of the widthwise end P2 of the paper P. It is pushed in the B direction. Further, the image surface 2 of the central portion P1 in the width direction of the paper P is on the central portion side in the width direction with respect to the projecting member 110, and by hitting the pressing member 114, the curl side of the central portion P1 in the width direction of the paper P. Paper P is pressed in the direction of arrow C. As a result, the curl of the paper P is corrected, and when the paper P is conveyed to the fixing portion 18, the disorder of the conveying posture of the paper P is suppressed.

In the above-mentioned transport device 100, the top of the pressing member at the center in the width direction is separated from the top of the protruding member at the end in the width direction in the thickness direction of the paper when viewed from the transport direction of the paper. Curling during image formation on the back surface of the paper P is suppressed, and wrinkles on the paper P are reduced.

Further, in the image forming apparatus 10, when the paper P is conveyed along the reversal path 102, the central portion P1 of the image surface 2 of the paper P in the width direction protrudes toward the pressing member 114 from the end portion P2 in the width direction. It is configured to curl as if it were. Then, the protruding member 110 hits the paper P from the anti-image surface 4 of the paper P, and the pressing member 114 hits the paper P from the image side 2 of the paper P, so that the curl of the paper P is corrected. Therefore, in the transport device 100, wrinkles of the paper P at the time of forming an image on the back surface of the paper P are suppressed as compared with a configuration in which the protruding member does not hit the paper from the anti-image surface.

Further, in the transport device 100, the projecting member 110 is arranged outside the short side 6 of the A4 size paper P (A4) in the axial direction. When the A4 size paper P (A4) passes through the fixing portion 18, curling is unlikely to occur, but when the paper P larger than the A4 size passes through the fixing portion 18, curling is likely to occur. As a result, when the paper P having a size larger than the short side 6 of the A4 size paper P (A4) is conveyed along the reversing path 120, the paper P hits the projecting member 110 and the end portion P2 in the width direction of the paper P. The curl is corrected. Therefore, in the above-mentioned transport device 100, the curl at the time of image formation on the back surface of the paper P is increased as compared with the configuration in which the protruding member is arranged only on the inner side in the axial direction from the short side of the A4 size paper. It is suppressed and the wrinkles of the paper P are reduced. In addition, it does not interfere with the paper transport sent from the short side of A4.

Further, in the transport device 100, the pressing member 114 is arranged outside the short side 6 of the A4 size paper P (A4) in the axial direction, and is located outside the short side 6 of the A4 size paper P (A4). When the large-sized paper P is conveyed, the paper P hits the pressing member 114. Therefore, in the above-mentioned transport device 100, the curl at the time of forming an image on the back surface of the paper P is compared with the configuration in which the pressing member is arranged only on the inner side in the axial direction from the short side of the A4 size paper. Is suppressed, and wrinkles on the paper P are reduced. In addition, it does not interfere with the paper transport sent from the short side of A4.

Further, in the transport device 100, the projecting member 110 and the pressing member 114 are arranged so that at least a part of the projecting member 110 and the pressing member 114 overlap in the transport direction of the paper P. Therefore, in the above-mentioned transport device 100, curling during image formation on the back surface of the paper P is suppressed as compared with the case where the projecting member and the pressing member are arranged apart from each other in the paper transport direction. Wrinkles on paper P are reduced.

Further, in the transport device 100, the protruding member 110 is a protrusion protruding from the guide 112 of the reversing path 102. Therefore, in the above-mentioned transport device 100, the structure is simple as compared with the configuration in which the projecting member does not project from the guide.

Further, in the transport device 100, the top 110B of the protruding member 110 is curved in an R shape, and the angle between the upstream portion of the top 110B of the protruding member 110 and the line along the transport direction of the paper P is the protruding member 110. It is smaller than the angle between the portion on the downstream side of the top 110B and the line along the transport direction of the paper P. As a result, the paper P is smoothly conveyed along the projecting member 110. Therefore, in the above-mentioned transport device 100, poor transport of the paper P is suppressed as compared with a member having an isosceles triangle shape of the protrusion.

Further, in the transport device 100, the pressing member 114 is a protrusion protruding from the guide 116 of the reversing path 102. Therefore, in the above-mentioned transport device 100, the structure is simple as compared with the configuration in which the pressing member does not protrude from the guide.

[Second Embodiment]
Next, the transport device and the image forming device according to the second embodiment will be described with reference to FIG. The same components as those of the above-described first embodiment are designated by the same numbers, and the description thereof will be omitted.

The image forming apparatus of the second embodiment is partially different from the overall configuration of the image forming apparatus 10 (see FIG. 1) of the first embodiment, and the conveying device 130 is provided in place of the conveying device 100 (see FIG. 1). ing. As shown in FIG. 6, in the transport device 130, a pair of transport rolls 132 as an example of two transport rolls are provided inside the projecting members 110 arranged at both ends in the device depth direction (arrow D direction). It is provided. Two sets of the pair of transport rolls 132 are arranged apart from each other in the device depth direction (arrow D direction). That is, the pair of transport rolls 132 are provided on the central portion side of the projecting member 110 in the width direction of the reversing path 102. The pair of transport rolls 132 are arranged on one transport roll 134 arranged on the side of the projecting member 110 with respect to the transport direction of the paper P and on the opposite side of the projecting member 110 with respect to the transport direction of the paper P. The transport roll 136 and the like are provided. The pair of transport rolls 134 and 136 are brought into contact with each other to form a contact portion 138. Here, the other transport roll 136 of the pair of transport rolls 132 is an example of the pressing member, and the contact portion 138 of the other transport roll 136 is an example of the top. The other transport roll 136 includes a rotation shaft 124 that is common to the other roll 106B of the transport roll 106. Further, one transport roll 134 includes a rotation shaft 122 common to one roll 106A of the transport roll 106.

The other transport roll 136 of the pair of transport rolls 132 is configured to hit the paper P from a direction opposite to the pushing direction of the paper P by the projecting member 110. Further, the contact portion 138 of the other transport roll 136 is arranged so as to overlap the top portion 110B of the projecting member 110 when viewed from the transport direction of the paper P. Further, the projecting member 110 hits the paper P from the anti-image surface 4 of the paper P, and the transport roll 136 hits the paper P from the image side 2 of the paper P.

Further, as an example, when the A4 size paper P (A4) is conveyed to the reversing path 102, the pair of transfer rolls 132 are axially outside the short side 6 of the A4 size paper P (A4). Have been placed.

In the image forming apparatus 10 (see FIG. 1), when the paper P is conveyed along the reversal path 102 after fixing, the central portion P1 in the width direction of the image surface 2 of the paper P is more than the end portion P2 in the width direction of the paper P. It is easy to curl so as to project toward the other transport roll 136. In the above-mentioned transport device 130, the image surface 2 of the central portion P1 in the width direction of the paper P is on the central portion side in the width direction with respect to the projecting member 110, and the paper P is formed by the other transport roll 136 of the pair of transport rolls 132. It is pressed in the direction of arrow C from the curl side of the central portion P1 in the width direction of the above (see FIG. 5 (B)). Further, the anti-image surface 4 of the widthwise end P2 of the paper P is pushed by the projecting member 110 in the direction of the arrow B opposite to the curl direction of the widthwise end P2 of the paper P (FIG. 5 (B). )reference). As a result, the curl of the paper P is corrected, and the disorder of the transport posture of the paper P is suppressed.

In the above-mentioned transport device 130, the top of the pressing member at the center in the width direction is separated from the top of the protruding member at the end in the width direction in the thickness direction of the paper when viewed from the transport direction of the paper. Curling during image formation on the back surface of the paper P is suppressed, and wrinkles on the paper P are reduced.

In the above-mentioned transfer device 130, the same actions and effects can be obtained with respect to the same configuration as the transfer device 100 of the first embodiment, and therefore the description of these actions and effects will be omitted.

Further, in the above-mentioned transport device 130, the other transport roll 136 of the pair of transport rolls 132 is an example of the pressing member, and hits the paper P from the image surface 2 of the paper P. Therefore, the structure of the transfer device 130 is simple as compared with a configuration in which the pressing member is not a transfer roll of one of the two transfer rolls.

[Third Embodiment]
Next, the transport device and the image forming device according to the third embodiment will be described with reference to FIG. 7. The same components as those of the first and second embodiments described above are designated by the same numbers, and the description thereof will be omitted.

The image forming apparatus of the third embodiment is partially different from the overall configuration of the image forming apparatus 10 (see FIG. 1) of the first embodiment, and the conveying device 150 is provided in place of the conveying device 100 (see FIG. 1). ing. As shown in FIG. 7, the transport device 150 is provided with a projecting member 152 supported by a guide 154 via a spring 156 as an urging member. The projecting member 152 is provided at the end of the reversing path 102 in the width direction. The shape of the projecting member 152 is the same as the shape of the projecting member 110 (see FIG. 3) of the transport device 100 of the first embodiment. The projecting member 152 projects from the side of one roll 106A of the transport roll 106 to the side of the other roll 106B beyond the nip N of the pair of transport rolls 106.

In the transport device 150, when the paper P transported on the reversing path 102 hits the projecting member 152, the spring 156 contracts according to the thickness of the paper P and the strength of the stiffness, and the projecting member 152 retracts. As a result, for example, when thick paper P or the like that does not need to correct the transport posture of the paper P is transported along the reversing path 102, it is possible to prevent the protruding member 152 from obstructing the transport of the paper P.

In the above transport device 150, the paper is not arranged so that the top of the pressing member at the center in the width direction overlaps the top of the protruding member at the end in the width direction with respect to the paper transport direction. Curling during image formation on the back surface of P is suppressed, and wrinkles on the paper P are reduced.

[Fourth Embodiment]
Next, the transport device and the image forming device according to the fourth embodiment will be described with reference to FIG. The same components as those in the first to third embodiments described above will be assigned the same number and the description thereof will be omitted.

The image forming apparatus of the third embodiment is partially different from the overall configuration of the image forming apparatus 10 (see FIG. 1) of the first embodiment, and a conveying device 170 is provided in place of the conveying device 100 (see FIG. 1). ing. As shown in FIG. 8, the transport device 170 is provided with a projecting member 172 supported by the guide 174. The projecting member 172 is made of a film-like member. The projecting member 172 is bent at an intermediate portion, and one end portion 172A is attached to the guide 174. The other end portion 172B extends obliquely from one end portion 172A toward the downstream side in the transport direction of the paper P. The end 173 of the other end 172B projects from the side of one roll 106A of the transport roll 106 to the side of the other roll 106B beyond the nip N of the pair of transport rolls 106. The other end 172B of the projecting member 172 can be flexed and deformed when a force is applied in a direction intersecting the surface direction. The projecting member 172 is provided at the end of the reversing path 102 in the width direction.

In the transport device 170, when the paper P transported through the reversing path 102 hits the other end 172B of the projecting member 172, the other end 172B is downstream of the paper P depending on the thickness and stiffness of the paper P. It bends and deforms in the lateral direction (lower side in the height direction of the device). As a result, for example, when thick paper P or the like that does not need to correct the transport posture of the paper P is transported along the reversing path 102, it is possible to prevent the protruding member 152 from obstructing the transport of the paper P.

In the above transport device 150, the paper is not arranged so that the top of the pressing member at the center in the width direction overlaps the top of the protruding member at the end in the width direction with respect to the paper transport direction. Curling during image formation on the back surface of P is suppressed, and wrinkles on the paper P are reduced.

In the transport device of the first to fourth embodiments, the shape of the protruding member can be changed. Further, in the transport device of the first to fourth embodiments, the pressing member is arranged outside the short side of the A4 size recording medium in the axial direction, but the present invention is limited thereto. is not it. For example, instead of or in addition to the transfer device of the first to fourth embodiments, the pressing member may be arranged axially inside the short side of the A4 size recording medium.

Further, in the transfer device of the first to fourth embodiments, the projecting member and the pressing member are arranged at the portion where the paper P is conveyed in the vertical direction, but the present invention is not limited to this. For example, the projecting member and the pressing member of the present invention may be arranged at a portion where the paper P is conveyed in the lateral direction.

Further, the image forming apparatus in which the conveying apparatus of the first to fourth embodiments is arranged is provided with a transfer belt 52, but the present invention is not limited thereto. For example, the present invention can also be applied to an image forming apparatus in which a toner image is directly transferred from an image holder to a recording medium.

Further, although the image forming apparatus in which the transporting apparatus of the first to fourth embodiments is arranged has a structure in which a color image is formed, the present invention can also be applied to a monochromatic image forming apparatus.

Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It is obvious to the trader.

2 Image surface 4 Anti-image surface 6 Short side 10 Image forming device 14 Toner image forming part (example of image forming part)
18 Fixing part (an example of image forming part)
100 Transport device 102 Inversion path 104 Transport roll 106 Transport roll 106A roll (an example of one transport roll)
106B roll (an example of the other transport roll)
110 Protruding member 110A Upstream side inclined part (example of upstream side part)
110B Top 110C Downstream slope (an example of downstream part)
112 Guide 114 Pressing member 114B Top 116 Guide (an example of another guide)
130 Transfer device 132 A pair of transfer rolls (an example of two transfer rolls)
136 Transport roll (an example of pressing member)
138 Contact part (an example of the top of the pressing member)
150 Conveying device 152 Protruding member 154 Guide 170 Conveying device 172 Protruding member 174 Guide N Nip P Paper (an example of recording medium)
P1 central part P2 end part

Claims (10)

An inversion path in which the recording medium is conveyed to the image forming unit, and then the front and back of the recording medium are inverted and conveyed to the image forming unit.
A pair of transport rolls provided in the reversal path and transport the recording medium,
It is provided only at the widthwise end of the reversal path and projects from the side of one transport roll to the side of the other transport roll beyond the nip of the pair of transport rolls to extend the widthwise end of the recording medium. With the protruding member to push,
It is provided on the central side with respect to the projecting member in the width direction of the reversal path, hits the recording medium from a direction opposite to the pushing direction of the recording medium by the projecting member, and the top is viewed from the transport direction of the recording medium. A pressing member arranged so as to overlap the top of the protruding member,
And having a,
In the image forming portion, when the recording medium is conveyed along the inversion path, the central portion of the image surface of the recording medium on which the image is formed in the width direction is closer to the pressing member than the end portion in the width direction. It is configured to curl so that it protrudes into the image.
The protruding member hits the recording medium from the anti-image surface on which the image of the recording medium is not formed.
The pressing member is a transport device that hits the recording medium from the image plane of the recording medium. The transport device according to claim 1 , wherein the top of the pressing member is arranged downstream of the top of the protruding member in the transport direction of the recording medium when viewed from a direction orthogonal to the transport direction of the recording medium. .. The transport device according to claim 1 or 2, wherein the protruding member is arranged outside the short side of the A4 size recording medium in the axial direction. The transport device according to claim 3, wherein the pressing member is arranged outside the short side of the A4 size recording medium in the axial direction. The transport device according to any one of claims 1 to 4, wherein the projecting member and the pressing member are arranged so that at least a part of the projecting member and the pressing member overlap in the transport direction of the recording medium. The projecting member, Ri projection der projecting from the guide of the reversing path,
The top of the protrusion is curved in an R shape, and the angle between the portion on the upstream side of the top of the protrusion and the line along the transport direction of the recording medium is the portion on the downstream side of the top of the protrusion and the recording medium. The transport device according to any one of claims 1 to 5, which is smaller than the angle with the line along the transport direction of the above. The projecting member is supported by a guide of the reversing path via an urging member, and when the recording medium conveyed along the reversing path hits the projecting member, the urging member shrinks. The transport device according to any one of claims 1 to 5, wherein the projecting member can be retracted. The transport device according to any one of claims 1 to 7, wherein the pressing member is a protrusion protruding from another guide of the reversal path. 6. Conveyor device. A toner image forming portion that forms a toner image on the surface of the recording medium,
A fixing portion for fixing the toner image on the surface of the recording medium by heating and pressurizing, and a fixing portion.
The transport device according to any one of claims 1 to 9, which is arranged downstream of the fixing portion in the transport direction of the recording medium.
An image forming apparatus having.

Images